Whirring sound in air intake duct

CBRASSO

MEMBER
2001 FORD F-150
4.6L
V8
2WD
AUTOMATIC
170,000 MILES

Okay, I had s code 1401 so I replaced the EGR back pressure sensor and the 2 hoses attached to it. The tubes going down to exhaust were plugged with hose fragments so I removed it and cleaned it out. Also cleaned throttle body with throttle body cleaner. Also replaced the hose from the canister purge valve to throttle body. Now with all this done there is a whirring sound as if the air intake duct had an obstruction in it. Any ideas on what this would be? Thanks in advance!

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

So normally this noise is caused by air escaping but due to what you are saying happened I suspect there is an issue with the IAC or the throttle body itself. There is a chance that you have damaged the throttle body because these have a coating that cannot be cleaned. If you clean this off, there is a chance you have air passing the throttle plate causing the noise. Also, the position sensor can be damaged so they don't want you cleaning them. Do you know if the idle has changed at all since you did this?

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Sunday, December 8th, 2019 AT 6:15 PM

CBRASSO

MEMBER
43 POSTS

Thanks for the reply. After I changed the sensor I had the code P0401 do I took TB and EGR off and found clogged ports. Before I changed the sensor I had the P1401 code but P0401 after.

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Monday, December 9th, 2019 AT 11:19 AM

KASEKENNY

MECHANIC
18,907 POSTS

So this P0401 wants you to run the KOER test to see if you get P1408. If not then it tells you to check the EGR system. Looks like you found the issue. You should be able to clear the codes and they won't come back.

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